Present electro-optical storage devices include Compact Disc Read Only Memory devices (CD-ROMs) that store digital information. The information is either or both audio and visual in nature. The information can also include data. CD ROMs comprise a plastic or "glass" disc that is coated with a metallic surface. The surface is etched or cut such that when placed in a CD ROM reader and spun at high speed, the etched pattern may be identified by a laser or other scanning method.
By their form, function and manufacture, CD ROMs are generally indistinguishable from one another. It is also generally difficult, if not impossible, to identify the nature or content of the information on a given CD ROM by visual inspection alone. It is therefore necessary to provide CD ROMs with a physical, unique mark or label.
The capability of a CD ROM to faithfully represent the information contained thereon is in large part dependent on the ability of the disc to be placed into a sustained, steady high speed spin about its physical center. This high speed spin presents complications to the marking methods employed.
Traditional ink based marketing methods in which the ink is applied directly to the disc must use an ink that will remain in place during sustained high speed spin. Additionally, the ink must be non-deleterious to the material of the disc. Use of conventional writing instruments, such as felt tip pens, is generally unsatisfactory since the ink may particulate and separate from the disc with the potential for becoming lodged in the mechanism of the disc reader. In addition, marking in this way does not present a professional appearance, especially if the CD ROMs are to be sold or used commercially.
Printers specially adapted for printing onto compact discs are available. However, the cost of such printers is prohibitive to those who produce CD ROMs in low volumes.
An alternative to using an ink marker directly on the disc is to use a label, usually a self-adhesive label, that is subsequently attached to the disc. Because of the high speed at which the disc must be spun, it is essential that the label be affixed in such a way that the overall balance of the disc is not adversely affected. In particular, it is necessary that the center of balance of the disc remains about its geometric center. Labels which are not concentrically affixed to the discs, for example, "half-moon" or semi-circular labels, have previously caused malfunctions and often rendered the discs virtually useless.
A known manual device for concentrically applying a self-adhesive label to a compact disc comprises a first member having a cylinder closed at one end by a slightly convex exterior face with a central aperture corresponding approximately to the size of the central aperture of the label, and a second member having a first portion with a diameter approximate to the diameter of the aperture of the first member and a second portion having a diameter approximate to the diameter of the central aperture of the compact disc. The first and second portions together form a shoulder against which the compact disc is seated.
In use, the operator must initially position an adhesive label on the first member so that its adhesive surface is uppermost. The label aperture is aligned with the central aperture of the end face of the cylinder. This step alone can be difficult because of the tendency of the label to stick to the operator's fingers and hence move off-center when the operator attempts to withdraw his/her fingers in order for the compact disc to be pressed onto the label. Also, there is a tendency for the label to curl upwards when the operator is not holding the label down.
Once the label is in its desired position on the first member, the compact disc which is retained against the shoulder portion of the plunger can be pressed down onto the label. In order to achieve the desired concentric alignment between the label and the disc, it is necessary to press firmly the disc against the shoulder portion while pushing the first portion of the plunger through the aligned apertures of the first member and the label.
Since the surface of the first member against which the label and compact disc are pressed is not planar, further care has to be taken to ensure that no air bubbles are trapped between the label and the disc. Such air bubbles are not only unsightly, but may also cause balancing problems in the CD ROM reader.
It will be appreciated that this known device therefore relies upon the skill and manual dexterity of the operator in order to achieve correct alignment of the label and the compact disc. Moreover, the device is reliant upon the operator being sufficiently well-organized to keep the two components in close proximity ready for use.
Accordingly, it is an object of the present invention to provide a device that overcomes the aforementioned problems and is inexpensive to produce, manually operable, permits reliable alignment of the label and the compact disc, and substantially eliminates the opportunity for operator error.